Federal and state environmental regulations require the operators of sanitary landfill operations to periodically cover disposed solid waste with six inches of earthen material to control disease, insects, fires, odors, blowing litter, and scavenging. For example, most jurisdictions require such covering of sanitary landfills at the end of each operating day, or at more frequent intervals if necessary. This covering requirement and the cover material is known as "daily cover" or "periodic cover" where the regulatory interval is more than one day, e.g., three days. As used herein, "daily cover" is intended to include daily and periodic cover for sanitary landfills, such as municipal solid waste (MSW) landfills, rubble landfills and land clearing debris landfills, and industrial waste landfills.
Each day's garbage, trash or rubble layer is covered at the end of the day and further garbage, trash or rubble layers are then spread directly on top of the daily cover for the previous day. In many landfill sites the soil used for the daily cover must be mined at the landfill site or purchased from an outside source and, due to the high rate of soil consumption, comprises a substantial cost item. Moreover, it has been recognized that multiple earth fill layers used in this way consume a significant volume of the valuable landfill space which might otherwise be used for receiving garbage, trash or rubble. It is well known that many communities are rapidly exhausting their available landfill acreage and it is therefore desirable to reduce the consumption rate of the available landfill volume. Accordingly, federal and state regulations allow alternative, more compressible, daily cover materials in lieu of the six inches of earthen material so long as the alternative materials provide the requisite level of protection.
Several such alternative daily cover materials are known in the art. One alternative, disclosed in U.S. Pat. No. 4,519,338 to Kramer et al, comprises hardenable plastic foam cover which is applied to the waste material by spraying. Similarly, companies such as 3M Environmental Protection Products of St. Paul, Minn., Chubb Environmental Security of Exton, Pa., and Russmer of Westchester, Pa., have all developed synthetic foams which can be sprayed onto a landfill face each day to function as a daily cover.
One disadvantage of such foam spray daily covers is that the high pressure spray equipment utilized to apply the foam tends to blow away the waste material to which it is applied. Additionally, the foam spray solution is expensive, typically 12 to 15 cents per square foot, substantially more expensive than dirt. Furthermore, weather restrictions, such as heavy rain or extreme cold and wind, hampers both the installation and performance of foam covers.
Another disadvantage of the foam daily cover substitutes is that it cannot be easily formulated from recycled materials. The increasing sensitivity towards the environment by society at-large has greatly increased the demand for using recycled products. State and municipal environmental officials, who operate or regulate most landfills, have been especially active in encouraging use of recycled products. Among the advantages of recycling is the fact that the waste material is converted into useful products rather than taking up rapidly depleting landfill space. Hence, such officials are making great efforts to integrate recycled materials into operations under control of their governments, including landfill operations.
Another alternative to using earthen material as a daily cover is disclosed in U.S. Pat. Nos. 4,909,667 to DeMello and 4,927,317 to Acosta. DeMello and Acosta disclose a geotextile or sheet-like member, such as canvas and the like, which is laid over the working face of a landfill at the end of the operating day. Similar geotextile daily covers include the Fabrisoil.RTM. non-woven polypropylene geotextile manufactured by the Phillips Fiber Corp. of Greenville, S.C. as well as the Sani-Cover.TM. polypropylene geotextile manufactured by Amoco Fibers Corp. of Atlanta, Ga. A key disadvantage of geotextile covers is their expense which may be as high as $2.25 per square yard. In addition, geotextiles are subject to mechanical damage, such as tears, punctures and the like, require replacement or repair and are difficult to apply in inclement weather.